engine shudder and rpm drop while coming to stop (184K miles now-FWD 2000 V70XC)
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    1. #1
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      engine shudder and rpm drop while coming to stop (184K miles now-FWD 2000 V70XC)

      flush was performed. Transtune from seafoam was added.
      ETM is xemodex.MAF was cleaned.

      when i coast to stop rpms would drop for a moment to 650-700-750 and then would go back up to 850-900. At the same time I would experience a slight shudder.

      Also when coming away from the stop or just pushing the accel pedal when speed is not to high, I hear a rumbling noise from the transmission as it is having a hard time. Revs do not go up as when the trans is slipping, but that rumbling is very audible.

      I think that my torque converter is going. Would these symptoms be indicative of the problems with torque converter?
      (2004 XC90 2.5T AWD -- 18X kmiles)
      (2003 V70 2.4i AT FWD -- 18X kmiles)
      (2001 V70 T5M FWD -- 16X kmiles)

    2. #2
      Member VolvoGuy50's Avatar
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      Quote Originally Posted by tolian2 View Post
      flush was performed. Transtune from seafoam was added.
      ETM is xemodex.MAF was cleaned.

      when i coast to stop rpms would drop for a moment to 650-700-750 and then would go back up to 850-900. At the same time I would experience a slight shudder.

      Also when coming away from the stop or just pushing the accel pedal when speed is not to high, I hear a rumbling noise from the transmission as it is having a hard time. Revs do not go up as when the trans is slipping, but that rumbling is very audible.

      I think that my torque converter is going. Would these symptoms be indicative of the problems with torque converter?
      Any CEL's or up arrows?

      Mine used to drop RPM like that too. Coming off load quickly - i.e. accelerated hard, then hit the clutch as I approach the next traffic light on a road. Never got to the bottom of it, but it might have been an AFR issue of some sort.

      Not sure on the rumbling noise though.
      '98 S70 T5 Auto - The Track Car --> My Build Thread
      '92 745 NA+TT Auto - The Daily Driver --> My Mods Thread
      '95 855 NA Auto - Gone and missed....
      '01 Mazda Tribute LX-V6 AWD - Gone and NOT missed!

    3. #3
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      Quote Originally Posted by VolvoGuy50 View Post
      Any CEL's or up arrows?

      Mine used to drop RPM like that too. Coming off load quickly - i.e. accelerated hard, then hit the clutch as I approach the next traffic light on a road. Never got to the bottom of it, but it might have been an AFR issue of some sort.

      Not sure on the rumbling noise though.
      no codes of any sort: not on engine or on trans module (as read by elm 327 to usb reader)
      (2004 XC90 2.5T AWD -- 18X kmiles)
      (2003 V70 2.4i AT FWD -- 18X kmiles)
      (2001 V70 T5M FWD -- 16X kmiles)

    4. #4
      Member Big Will's Avatar
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      Quote Originally Posted by tolian2 View Post
      no codes of any sort: not on engine or on trans module (as read by elm 327 to usb reader)
      I am having this problem intermittently in a 2000 XC manual in Sweden. No CEL either. Plugs are new within the last 10K kms so it's a bit of a mystery. Perhaps we'll find a common solution to this.
      98 V70 AWD M58 Manual: Wothrline tune, 15G turbo/angled flange, White injectors, R Manifold, TME Downpipe, TME Exhaust, EST Intake, IPD Swaybars + endlinks, Volvo Strut Brace, Íhlins Roadholding Suspension + Springs, 302mm ATE front rotors, vented R rears , SS Brake lines, E-spec C70 Jewels w/ 55w HIDs.

    5. #5
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      Get a slight shudder when at stop lights. No codes. Everything is new or near new. At 175k. Have come to accept it.
      04 V70 2.5T AWD - AUTOTECH | SNABB | OBX | MAGNAFLOW | SNABB | BILSTEIN | EIBACH

    6. #6
      I don't get the shudder, but my RPMs do dip down a little bit, particularly after a hard stop off a freeway. I have an XeMODeX ETM, new MAF, and transmission is in fine shape. I don't know what it is either, and I know a lot of other people have the same thing with no other issues.

    7. #7
      Junior Member heavyiron's Avatar
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      My rpms drop at lights down to the 650rpm range and then come back up, but ONLY with the A/C on. Otherwise it idles and comes off a load to a stop with no drop in Rpm. 2000xc with 203k miles and a complete tuneup and service within past 500 miles. new plugs, coilpacks, air filter, fuel filter, injector orings, cam solenoid, blah, blah - no difference.

    8. #8
      Junior Member 1999s70's Avatar
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      How about the Idle Control Valve? I had similar symptoms to what's in this post, also with a new ETM and MAF. My mechanic suggested the ICV, since mine was the original. Worked like a charm.
      Best regards,
      George

      1999 S70, Pewter, Non-Turbo, Auto Tranny, 530K miles, Original Owner, XemodeX ETM
      I'm not the fastest off the line, but if the race lasts a million miles I just might win.

    9. #9
      Junior Member heavyiron's Avatar
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      I did not think the ETM units had them. I will have to check that.

    10. #10
      Junior Member adamjjohn203's Avatar
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      WHere is the IAC located on 99+ models...

    11. #11
      Member VolvoGuy50's Avatar
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      Quote Originally Posted by heavyiron View Post
      I did not think the ETM units had them. I will have to check that.
      It's no where to be found on the wiring diagrams, so that'd my guess.

      Quote Originally Posted by adamjjohn203 View Post
      WHere is the IAC located on 99+ models...
      Apparently nowhere, lol
      '98 S70 T5 Auto - The Track Car --> My Build Thread
      '92 745 NA+TT Auto - The Daily Driver --> My Mods Thread
      '95 855 NA Auto - Gone and missed....
      '01 Mazda Tribute LX-V6 AWD - Gone and NOT missed!

    12. #12
      Junior Member adamjjohn203's Avatar
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      Interested to see what the member above paid to have fixed since his car is a 99+

    13. #13
      the RPM on my '00 XC also drops in a similar manner when coming to a stop, would love to find a solution.
      1998 S70 T5, 239k '00R 302s/DIY AEM BCS/IPD Stage 1 ECU/IPD 3" Turboback/Comets/OMP brace
      2006 Mini Cooper S, 6-speed, 74k 15% pulley, JCW exhaust/intake/suspension

    14. #14
      Member VolvoGuy50's Avatar
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      Quote Originally Posted by adamjjohn203 View Post
      Interested to see what the member above paid to have fixed since his car is a 99+
      Which member above what post?
      '98 S70 T5 Auto - The Track Car --> My Build Thread
      '92 745 NA+TT Auto - The Daily Driver --> My Mods Thread
      '95 855 NA Auto - Gone and missed....
      '01 Mazda Tribute LX-V6 AWD - Gone and NOT missed!

    15. #15
      Junior Member adamjjohn203's Avatar
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      Quote Originally Posted by 1999s70 View Post
      How about the Idle Control Valve? I had similar symptoms to what's in this post, also with a new ETM and MAF. My mechanic suggested the ICV, since mine was the original. Worked like a charm.
      This one....

    16. #16
      Member VolvoGuy50's Avatar
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      Quote Originally Posted by adamjjohn203 View Post
      This one....
      Ah, yeah...I'd like to know the same thing. Having no IAC on an ETM setup makes sense...why bother adding another device when you can just crack the throttle open a bit? When I tossed my IAC, that's how I ran my car.
      '98 S70 T5 Auto - The Track Car --> My Build Thread
      '92 745 NA+TT Auto - The Daily Driver --> My Mods Thread
      '95 855 NA Auto - Gone and missed....
      '01 Mazda Tribute LX-V6 AWD - Gone and NOT missed!

    17. #17
      Junior Member 1999s70's Avatar
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      The ICV is in the air intake, just past the output from the MAF. If I recall correctly, the business end of it is stuck into the intake hose, the unit itself is held in by two screws and there is a wiring connector. The ICV purges excess air from the intake line when you slow down, and its failure is most apparent when you go from high engine speed to idle, particularly quickly, like a hard brake when coming off a highway onto an exit ramp. A failing ICV will give almost identical symptoms to a failing MAF, except that the ICV only acts up when you're at low engine speeds, while the MAF will act up at all speeds.

      Why the ICV is a good question, actually. I have no idea, except that the ETM can't purge excess air, only regulate what goes into the manifold. And, of course, it can't anticipate anything.

      I had a similar shudder problem as described by the OP, and thought it was the MAF, except that I had just replaced that component. I wasn't thinking ICV because I, too, thought that this would have been obsoleted. I was surprised when my mechanic asked whether I had ever replaced the ICV, and I told him that I hadn't, and that I was running the original unit. So, based on about 35 years of his experience, and the fact that my ICV had something over 350K miles on it, at the time, he advised that I replace it. And it worked. Since then, I've replaced the unit one other time when the same symptoms occurred.

      Tricky, to be sure, to distinguish between ICV, MAF and ETM, especially without VADIS.
      Best regards,
      George

      1999 S70, Pewter, Non-Turbo, Auto Tranny, 530K miles, Original Owner, XemodeX ETM
      I'm not the fastest off the line, but if the race lasts a million miles I just might win.

    18. #18
      Junior Member adamjjohn203's Avatar
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      Ahhhh I believe you are talking about the PTC.....The PTC stands for positive temperature coefficient and heats the blowby gasses before they enter the intake air pre-turbo. This helps to reduce the formation of ice crystals that can potentially damage your turbo or freeze up and block your breather over pressurizing your head and creating leaks in your seals.

    19. #19
      Junior Member 1999s70's Avatar
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      My car is not a turbo.
      Best regards,
      George

      1999 S70, Pewter, Non-Turbo, Auto Tranny, 530K miles, Original Owner, XemodeX ETM
      I'm not the fastest off the line, but if the race lasts a million miles I just might win.

    20. #20
      Former Advertiser TEPPERS AUTO SALES's Avatar
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      Mine was a 140K mile original MAF
      Fine now, (99T5).

    21. #21
      I have a new Bosch MAF and the issue persists so at least for me, it's not the MAF. George, could you take a picture of the ICV on your car?
      1998 S70 T5, 239k '00R 302s/DIY AEM BCS/IPD Stage 1 ECU/IPD 3" Turboback/Comets/OMP brace
      2006 Mini Cooper S, 6-speed, 74k 15% pulley, JCW exhaust/intake/suspension

    22. #22
      Member VolvoGuy50's Avatar
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      OK lets get some terms straight here since there's obv. some confusion.

      ICV or IAC = Idle Control Valve...99+ does not have these, therefore they are irrelevant to the OP's issue.
      PTC or PTC Resistor = positive temperature coefficient heating element. This is found on BOTH NA & Turbo cars. This is part of the PCV system and has NOTHING to do with ice crystals.
      ETM = Electronic Throttle Module. Pretty self explanatory. Throttle gate movement is control by an electric actuator instead of a steel cable. 99+ controls idle by opening or closing the throttle gate.

      Sorry for the durrr post, but if people are going to use abbreviation, everyone needs to know WTF they mean and if those components even exist on the car in question.
      '98 S70 T5 Auto - The Track Car --> My Build Thread
      '92 745 NA+TT Auto - The Daily Driver --> My Mods Thread
      '95 855 NA Auto - Gone and missed....
      '01 Mazda Tribute LX-V6 AWD - Gone and NOT missed!

    23. #23
      Junior Member adamjjohn203's Avatar
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      Quote Originally Posted by VolvoGuy50 View Post
      OK lets get some terms straight here since there's obv. some confusion.
      PTC or PTC Resistor = positive temperature coefficient heating element. This is found on BOTH NA & Turbo cars. This is part of the PCV system and has NOTHING to do with ice crystals.

      Sorry for the durrr post, but if people are going to use abbreviation, everyone needs to know WTF they mean and if those components even exist on the car in question.
      Taken from VolvoclubUK
      PTC Nipple in 90+Turbos.

      [Inquiry] What is the sensor or valve, with two wires and a vacuum hose connected to it, is that is attached to the turbo intake hose on my Mitsubishi turbo?

      [John Sargent/Dave Armstrong/Abe Crombie] This is the heated crankcase vent nipple (also referred to as the Positive Temperature Coefficient heater nipple) used on 90 and later where the air heater tube is deleted. The PTC nipple is mounted in the cold air intake pipe that runs from the air filter box to the turbo. It is in the elbow of the pipe, nearest the turbo. It has one or two vacuum hoses connected that run back to the oil trap. There is also an electrical connector about the size of a spark plug. Volvo decided that the preheat system which was thought would prevent throttle icing would not work on intercooled models due to cooling effect on air through the intercooler before it goes into the throttle. The heater is to vaporize the moist air that comes out of crankcase after start up and while driving in very cold weather. The LH fuel injection system on that car doesn't use the Intake Air Temperature sensor. Occasionally one can experienced a pressurized manifold with too much pressure in the crank case, causing oil to blow from the filler cap or the seals. This can be caused by the PTC nipple valve which can clog. All of the turbos since 1990 have a PTC and they tend to get clogged during cold weather.

    24. #24
      Junior Member 1999s70's Avatar
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      Until I can get a photo... I have replaced this part twice. Volvo called it an "Idle Control Valve" The part that I ordered from FCP Groton was number 1275634, which is described as an "Idle Control Valve." It's located in the hose that connects the MAF output to the ETM. You can Google "Volvo 1275634" and see pictures of it.
      Best regards,
      George

      1999 S70, Pewter, Non-Turbo, Auto Tranny, 530K miles, Original Owner, XemodeX ETM
      I'm not the fastest off the line, but if the race lasts a million miles I just might win.

    25. #25
      Former Advertiser TEPPERS AUTO SALES's Avatar
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      WOW!
      Not cheap

    26. #26
      Junior Member 1999s70's Avatar
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      Tell me about it, Jim . At least it's an easy DIY job, once you know the symptoms and that the car has such a part. Honestly, the whole air intake system on the S70 is a bunch of overpriced components with a high rate of failure and a high cost of maintenance, especially if you can't repair things yourself - while the rest of the car has been, overall, inexpensive to maintain.
      Best regards,
      George

      1999 S70, Pewter, Non-Turbo, Auto Tranny, 530K miles, Original Owner, XemodeX ETM
      I'm not the fastest off the line, but if the race lasts a million miles I just might win.

    27. #27
      Junior Member adamjjohn203's Avatar
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      Soo it looks like this is only on NA's... Here's how the part is listed...
      Air valve

      Stock Code: 1275634
      Price: $ 170.62
      Categories: Engine > Fuel system
      Assemblies: Fuel pressure pipes with fittings 4VALVE W/O TURBO, 1999-; Fuel pressure pipes with fittings 5CYL W/O TURBO
      ***Looks like it controls the fuel flow to the rail.....*****

    28. #28
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      Quote Originally Posted by 1999s70 View Post
      The ICV is in the air intake, just past the output from the MAF. If I recall correctly, the business end of it is stuck into the intake hose, the unit itself is held in by two screws and there is a wiring connector. The ICV purges excess air from the intake line when you slow down, and its failure is most apparent when you go from high engine speed to idle, particularly quickly, like a hard brake when coming off a highway onto an exit ramp. A failing ICV will give almost identical symptoms to a failing MAF, except that the ICV only acts up when you're at low engine speeds, while the MAF will act up at all speeds.

      Why the ICV is a good question, actually. I have no idea, except that the ETM can't purge excess air, only regulate what goes into the manifold. And, of course, it can't anticipate anything.

      I had a similar shudder problem as described by the OP, and thought it was the MAF, except that I had just replaced that component. I wasn't thinking ICV because I, too, thought that this would have been obsoleted. I was surprised when my mechanic asked whether I had ever replaced the ICV, and I told him that I hadn't, and that I was running the original unit. So, based on about 35 years of his experience, and the fact that my ICV had something over 350K miles on it, at the time, he advised that I replace it. And it worked. Since then, I've replaced the unit one other time when the same symptoms occurred.

      Tricky, to be sure, to distinguish between ICV, MAF and ETM, especially without VADIS.

      Thanks for the hint.
      and a "Wow!" to your almost 500K miles Volvo.
      (2004 XC90 2.5T AWD -- 18X kmiles)
      (2003 V70 2.4i AT FWD -- 18X kmiles)
      (2001 V70 T5M FWD -- 16X kmiles)